How to Make Seamless Textures(memo)

Making Seamless Textures
To really step up your game, you want to be able to edit your own textures and load them into Second Life. You use a free image editing tool like GIMP, or higher end applications like Paint Shop Pro and Photoshop. Photoshop has the most power, and arguably the most tutorials out there on the Internet, but it is more expensive.

What is a seamless texture? A seamless texture is one where you do not see an abrupt line when you repeat it side by side (either >1 repeats on a single prim, or many prims placed next to each other)

Photoshop has a tool called "Offset" which really eases the process of making seamless textures much easier. We will take as an example a stone texture. When you look at the stone texture, you will see that the inside of the image is naturally seamless, but its the borders where the image was cropped where you will end up with problems.

Offset shifts the image vertically or horizontally so that all of a sudden the border is now in the middle, where you can see the clash, and can edit the image to remove the problem.

The most useful tool to erase your seams is the clone tool, which picks up part of the image in one location and places it down in another. You can change the type of brush you use from round to square, from hard-edged to soft. You can also change how transparent your new brushstrokes are, which can be useful if you want to softly build up your seam-cover. There is no one right way -- different tools and methods are useful for different image/material types. There is no better teacher than experimentation.

Addendum: Removing Repeat Patterns
It is important to note that making something seamless might still not be enough, because you may have a glaring repeat problem (where highlights in the image make an obvious repetitive pattern that jars the eye). In these cases, you may have to sacrifice some authenticity, and some diversity within your texture, to smooth it out and have a more uniform surface that can repeat smoothly.

This may require working with the clone tool to get a more uniform spread of the surface material (and hiding any lighting/shadowing if you are working off of a photosourced image), and will probably require multiple offset actions to make sure that by covering up the older borders you have not added new seams.

In the example here, we have decided we want our marble to be fine-grained, which means we need to either repeat it in Second Life or we need to shrink it down within Photoshop and make a larger (or fuzzier) image that can be repeated 1x1.

At the end of the day, you may decide that the smoothing process required to hide the repeat pattern forces you to lose too much of your image, in which case you best option is to handle the repeat in your image editing application where you can manually get rid of repeats:
- copy the layers of your image and lay them out in a grid so your repeat is now in Photoshop
- use the clone tool to shape the image as you see fit
- this can be a very labor intensive process, as you do multiple offsets to examine for seams, and as you zoom in and out to check for excessively repeated patterns.